[III cranial nerve palsy and brainstem disfunction following retrobulbar anaesthesia].

There are currently various techniques of locoregional anaesthesia used in cataract surgery. One such technique, described by Knapp in 1884, is retrobulbar anaesthesia, which is currently applied in certain cases of outpatient eye surgery. At present, the most commonly used technique in the treatment of cataract is phacoemulsification with laser. This is very useful in cases of soft cataract, which responds well to laser treatment. It requires a small incision and local anaesthesia techniques with a good safety profile, such as sub-Tenon’s or peribulbar anaesthesia. However, the laser response may not be entirely satisfactory and accurate in very advanced and hardened cases of cataract. Such cases require, on the one hand, complete akinesia of the eye to correctly perform extracapsular extraction and, on the other hand, deeper anaesthesia because they require a larger incision and process that is more cumbersome and uncomfortable for the patient. Despite the improved safety profile of sub-Tenon’s anaesthesia, the retrobulbar technique makes faster and deeper anaesthesia possible in these cases, in addition to obtaining akinesia or fixing of the eyeball (which is not the case with sub-Tenon’s or peribulbar application techniques), which is critical to the success of the procedure. For the same reasons, its drawback is an increased risk of complications. There have been reports of neurological complications associated with this technique, such as decreased level of consciousness, seizures, abnormal heart rate and breathing, arterial hypotension and dysfunction of cranial nerves. A very rare complication is paralysis of the contralateral extrinsic ocular musculature. We present a case with brainstem involvement and complete paresis